Air conditioning system and control method thereof

Abstract

The invention relates to an air conditioning system and a control method thereof, and the air conditioning system comprises a refrigerant circulation loop; the liquid storage container is used for storing a refrigerant and is provided with a liquid inlet and a liquid outlet; the liquid inlet branch is provided with a liquid inlet valve with an on state and an off state, the first end of the liquid inlet branch is communicated with the liquid inlet, and the second end of the liquid inlet branch is communicated with the medium-pressure side pipeline; the liquid discharge branch is provided with a liquid discharge valve with a connected state and a disconnected state, the first end of the liquid discharge branch is communicated with the liquid outlet, and the second end of the liquid discharge branch is communicated with the refrigerant circulation loop; under the condition that the liquid inlet valve is in the on state, the pressure of the first end of the liquid inlet branch is smaller than that of the second end of the liquid inlet branch, and therefore a refrigerant in the refrigerant circulation loop is stored in the liquid storage container through the pressure difference. And under the condition that the liquid discharge valve is in the on state, the pressure of the first end of the liquid discharge branch is larger than that of the second end of the liquid discharge branch, so that the refrigerant in the liquid storage container is discharged to the refrigerant circulation loop through the pressure difference.

Description

Technical Field

[0001] The present disclosure relates to the field of refrigeration technology, and in particular to an air-conditioning system and a control method thereof. Background Art

[0002] A multi-split air conditioning system is an outdoor unit that can connect to multiple indoor units. Its refrigeration system is an outdoor unit that can transport refrigerant liquid to several indoor units through pipelines. By controlling the refrigerant circulation volume of the compressor and the refrigerant flow entering each indoor heat exchanger, the indoor cooling and heating load requirements can be met in a timely manner.

[0003] The current multi-split air-conditioning system can only realize conventional cooling mode and heating mode, and the heat exchange efficiency is low. Summary of the invention

[0004] Some embodiments of the present disclosure provide an air-conditioning system and a control method thereof, which can improve the energy efficiency of the air-conditioning system.

[0005] A first aspect of the present disclosure provides an air conditioning system, comprising:

[0006] The refrigerant circulation loop is provided with a compressor, an evaporator and a condenser. The high-pressure side pipeline is between the exhaust port of the compressor and the condenser, the medium-pressure side pipeline is between the condenser and the evaporator, and the low-pressure side pipeline is between the evaporator and the air intake port of the compressor;

[0007] A liquid storage container, used for storing refrigerant and having a liquid inlet and a liquid outlet;

[0008] A liquid inlet branch, on which a liquid inlet valve having an on state and an off state is provided, a first end of the liquid inlet branch is connected to the liquid inlet port, and a second end of the liquid inlet branch is connected to the medium-pressure side pipeline; and

[0009] A liquid discharge branch, on which a liquid discharge valve having an on state and an off state is provided, a first end of the liquid discharge branch is connected to the liquid outlet, and a second end of the liquid discharge branch is connected to the refrigerant circulation circuit;

[0010] Among them, when the liquid inlet valve is in the on state, the pressure at the first end of the liquid inlet branch is lower than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop can be stored in the liquid storage container by utilizing the pressure difference; when the liquid discharge valve is in the on state, the pressure at the first end of the liquid discharge branch is higher than the pressure at the second end, so that the refrigerant in the liquid storage container can be discharged into the refrigerant circulation loop by utilizing the pressure difference.

[0011] In some embodiments, the liquid storage container further has a pressure regulating port, and the air conditioning system further comprises:

[0012] A pressure relief branch, on which a balancing valve having an on state and an off state is provided, and a first end of the pressure relief branch is connected to the pressure regulating port;

[0013] When the balancing valve is in the on state, the pressure in the liquid storage container is released through the pressure relief branch.

[0014] In some embodiments, the second end of the drain branch is configured to communicate with the low-pressure side pipeline in the cooling mode, and the drain valve is configured to be in an on state in the cooling mode.

[0015] In some embodiments, the liquid inlet valve is in an on state in the defrost mode, the liquid discharge valve is in an on state in the initial stage of switching to the heating mode after the defrost ends, and the second end of the liquid discharge branch is configured to be connected to the high-pressure side pipeline in the heating mode.

[0016] In some embodiments, the liquid storage container further has a pressure regulating port, and the air conditioning system further comprises:

[0017] A pressurizing branch, on which a pressurizing valve having an on state and an off state is provided, and a first end of the pressurizing branch is connected to the pressure regulating port;

[0018] When the pressurizing valve is in the on state, the high-pressure side pipeline pressurizes the liquid storage container.

[0019] In some embodiments, the air conditioning system also includes an auxiliary drain branch, on which is provided an auxiliary drain valve with an on state and an off state, the first end of the auxiliary drain branch is connected to the liquid outlet, and the second end of the auxiliary drain branch is connected to the low-pressure side pipeline.

[0020] In some embodiments, the air-conditioning system also includes a unloading branch, a first end of the unloading branch is connected to the liquid inlet, a second end of the unloading branch is connected to the low-pressure side pipeline, and an unloading valve with an on state and an off state is provided on the unloading branch. The unloading valve is configured to be in an on state when the pressure in the liquid storage container is higher than a preset safety threshold.

[0021] In some embodiments, the liquid inlet and the pressure regulating port are arranged in the upper area of ​​the liquid storage container, and the liquid outlet is arranged in the lower area of ​​the liquid storage container.

[0022] In some embodiments, the refrigerant circulation loop further includes a four-way reversing valve and a gas-liquid separator, the four-way reversing valve is used to switch between the cooling mode and the heating mode, and the gas-liquid separator is arranged on the pipeline between the four-way reversing valve and the compressor suction port;

[0023] The air conditioning system further includes a pressure relief branch and a pressure increase branch, wherein the first ends of the pressure relief branch and the pressure increase branch are respectively connected to the pressure regulating port of the liquid storage container, the second end of the pressure relief branch is connected to the low-pressure side pipeline, and the second end of the pressure increase branch is connected to the high-pressure side pipeline;

[0024] The second end of the discharge branch is connected to the pipeline between the four-way reversing valve and the evaporator, the second end of the pressurization branch is connected to the pipeline between the exhaust port of the compressor and the four-way reversing valve, and the second end of the pressure relief branch is connected between the inlet of the gas-liquid separator and the four-way reversing valve.

[0025] In some embodiments, the liquid storage container is built into the outdoor unit assembly.

[0026] A second aspect of the present disclosure provides a control method for an air conditioning system based on the above embodiment, comprising:

[0027] Liquid collecting step: making the liquid inlet valve in an on state, and making the pressure at the first end of the liquid inlet branch less than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container;

[0028] Discharge step: When the refrigerant in the liquid storage container needs to be discharged to the refrigerant circulation loop, the discharge valve is turned on and the pressure at the first end of the discharge branch is greater than the pressure at the second end.

[0029] In some embodiments, the air conditioning system further includes a pressure relief branch and a pressurization branch, the pressure relief branch is provided with a balancing valve, the pressurization branch is provided with a pressurization valve, and the first ends of the pressure relief branch and the pressurization branch are respectively connected to the pressure regulating port of the liquid storage container; the control method further includes:

[0030] In the liquid collecting step, the balancing valve is turned on to reduce the pressure in the liquid storage container;

[0031] In the liquid discharge step, the pressurizing valve is turned on to increase the pressure in the liquid storage container.

[0032] In some embodiments, in the refrigerant adjustment function in the cooling mode and the heating mode, the liquid collection step includes:

[0033] The liquid inlet valve is in the on state, and when the pressure difference at both ends of the liquid inlet valve is less than the preset threshold value, the balancing valve is in the on state, and the drain valve and the pressurizing valve are both in the off state.

[0034] In some embodiments, the second end of the drain branch is configured to communicate with the low-pressure side pipeline in cooling mode;

[0035] In the refrigerant adjustment function under the refrigeration mode, the draining step includes: making the drain valve in an on state, and the inlet valve and the balance valve in an off state.

[0036] In some embodiments, in the refrigerant adjustment function under the refrigeration mode, the liquid discharge step further includes: when the internal pressure of the liquid storage container drops to the same level as the low-pressure side pipeline, the pressurizing valve is turned on.

[0037] In some embodiments, the second end of the drain branch is configured to communicate with the high-pressure side pipeline in the heating mode;

[0038] In the refrigerant adjustment function under the heating mode, the discharge step includes: putting the pressurizing valve in an on state to increase the pressure inside the liquid storage container to the pressure at the second end of the pressurizing branch, and putting the discharge valve in an on state.

[0039] In some embodiments, the second end of the drain branch is configured to communicate with the high-pressure side pipeline in the heating mode, and in the refrigerant transfer function,

[0040] During the defrosting process, the liquid collecting step includes: placing the liquid inlet valve in an on state, and placing the liquid discharge valve, the balancing valve and the pressurizing valve in an off state; and / or

[0041] In the initial stage of switching to the heating mode after defrosting, the pressurizing valve is turned on to increase the pressure inside the liquid storage container to the pressure at the second end of the pressurizing branch, and the drain valve is turned on.

[0042] Based on the above technical solution, the present disclosure has at least the following beneficial effects:

[0043] The air-conditioning system of the disclosed embodiment is additionally provided with a liquid storage container, and is connected with the medium-pressure side pipeline through a liquid inlet valve, and is connected with the refrigerant circulation loop through a liquid discharge valve. On the basis of realizing the conventional refrigerant mode and the heating mode, the excess refrigerant in the refrigerant circulation loop can be collected from a specific pressure side by using the pressure difference according to the actual heat exchange demand of the air-conditioning system, or the refrigerant in the liquid storage container can be discharged into the refrigerant circulation loop for replenishment according to the actual refrigerant demand, so as to achieve the best heat exchange effect, improve the heat exchange efficiency of the system, and improve the energy efficiency of the air-conditioning system. The refrigerant adjustment and transfer functions can be realized simultaneously by the same liquid storage container, which can simplify the system structure and improve the space utilization.

[0044] Moreover, the excess refrigerant collected from the medium-pressure side pipeline also has a relatively high pressure, so that the refrigerant can be smoothly stored in the liquid storage container. In the refrigeration mode and the defrost mode, the connection position of the second end of the liquid inlet branch is located upstream of the gas-liquid separator, and the excess refrigerant can be directly collected through the liquid storage container. There is no need to cooperate with the gas-liquid separator to store the refrigerant in the gas-liquid separator first. When needed, the refrigerant is allowed to enter the liquid storage container from the gas-liquid separator and then released from the liquid storage container, which can improve the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present application. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0046] Figure 1is a system schematic diagram of some embodiments of the air conditioning system disclosed herein;

[0047] Figure 2 It is a flow path schematic diagram of the air conditioning system of the present disclosure in a conventional cooling mode and a defrosting mode;

[0048] Figure 3 It is a schematic diagram of the flow path of the air conditioning system of the present disclosure in a conventional heating mode;

[0049] Figure 4 A schematic diagram of a flow path in a defrost mode when the air-conditioning system of the present disclosure realizes a refrigerant transfer function;

[0050] Figure 5 It is a schematic diagram of the flow path of the air-conditioning system of the present disclosure when realizing the refrigerant transfer function and entering the initial stage of the heating mode after the defrosting is completed;

[0051] Figure 6 A schematic diagram of a flow path for opening a liquid inlet valve to store refrigerant in a cooling mode when the air conditioning system of the present disclosure realizes a refrigerant adjustment function;

[0052] Figure 7 A schematic diagram of a flow path for storing refrigerant when the air-conditioning system of the present disclosure realizes the refrigerant adjustment function and the liquid inlet valve and the balance valve are opened simultaneously in the cooling mode;

[0053] Figure 8 A schematic diagram of a flow path for releasing refrigerant in a cooling mode when the air conditioning system of the present disclosure realizes a refrigerant adjustment function;

[0054] Fig. 9 A schematic diagram of a flow path for opening a liquid inlet valve to store refrigerant in a heating mode when the air conditioning system of the present disclosure realizes a refrigerant adjustment function;

[0055] Fig.10 A schematic diagram of a flow path when the air-conditioning system of the present disclosure realizes the refrigerant adjustment function and the liquid inlet valve and the balancing valve are opened simultaneously in the heating mode;

[0056] Fig.11 A schematic diagram of a flow path for releasing refrigerant in a heating mode when the air-conditioning system of the present disclosure realizes a refrigerant adjustment function;

[0057] Fig.12 The figure is a schematic diagram of the flow path of the air-conditioning system of the present disclosure releasing the refrigerant through the auxiliary drain valve in the heating mode.

[0058] It should be understood that the size of each part shown in the accompanying drawings is not drawn according to the actual proportional relationship. In addition, the same or similar reference numerals represent the same or similar components.

[0059] Description of Reference Numerals

[0060] 10. Outdoor unit components; 1. Liquid inlet branch; 2. Liquid discharge branch; 3. Pressure relief branch; 4. Pressurization branch; 5. Auxiliary liquid discharge branch; 6. Unloading branch;

[0061] 101, compressor; 102, oil separator; 103, four-way reversing valve; 104, external machine heat exchanger; 105, external machine throttling element; 106, gas-liquid separator; 107, liquid storage container; 108, liquid inlet valve; 109, liquid discharge valve; 110, pressurizing valve; 111, balancing valve; 112, unloading valve; 113, auxiliary liquid discharge valve;

[0062] 20. Indoor unit assembly; 201. Indoor unit heat exchanger; 202. Indoor unit throttling element. DETAILED DESCRIPTION

[0063] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0064] The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0065] In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other device without an intermediate device, or may not be directly connected to the other device but have an intermediate device.

[0066] All terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0067] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0068] Based on the above-mentioned embodiments of the present disclosure, in the absence of explicit negation or conflict, the technical features of one embodiment may be beneficially combined with one or more other embodiments.

[0069] The present disclosure provides an air conditioning system, such as Figures 1 to 12 As shown, in some embodiments, the air conditioning system includes:

[0070] A refrigerant circulation loop is provided with a compressor 101, an evaporator and a condenser. A high-pressure side pipeline is provided between the exhaust port of the compressor 101 and the condenser, a medium-pressure side pipeline is provided between the condenser and the evaporator, and a low-pressure side pipeline is provided between the evaporator and the air intake port of the compressor 101;

[0071] The liquid storage container 107 is used to store the refrigerant and has a liquid inlet A and a liquid outlet B;

[0072] A liquid inlet branch 1, on which a liquid inlet valve 108 having an on state and an off state is provided, a first end of the liquid inlet branch 1 is connected to the liquid inlet port A, and a second end of the liquid inlet branch 1 is connected to the medium-pressure side pipeline; and

[0073] A drain branch 2, on which a drain valve 109 having an on state and an off state is provided, a first end of the drain branch is connected to the liquid outlet B, and a second end of the drain branch is connected to the refrigerant circulation circuit;

[0074] Among them, when the liquid inlet valve 108 is in the on state, the pressure at the first end of the liquid inlet branch 1 is lower than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop can be stored in the liquid storage container 107 by utilizing the pressure difference; when the liquid discharge valve 109 is in the on state, the pressure at the first end of the liquid discharge branch 2 is higher than the pressure at the second end, so that the refrigerant in the liquid storage container 107 can be discharged into the refrigerant circulation loop by utilizing the pressure difference.

[0075] Specifically, a compressor 101, an evaporator and a condenser are provided on the refrigerant circulation circuit. Figure 1As shown, from the perspective of the installation position, the air-conditioning system includes an outdoor unit component 10 and an indoor unit component 20. The outdoor unit component 10 includes a compressor 101, an outdoor unit heat exchanger 104 and an outdoor unit throttling element 105. The indoor unit component 20 includes an indoor unit heat exchanger 201 and an indoor unit throttling element 202. The number of the indoor unit heat exchanger 201 can be one or more.

[0076] In the cooling state, the indoor heat exchanger 201 serves as an evaporator, the outdoor heat exchanger 104 serves as a condenser, the outdoor throttling element 105 is located downstream of the outlet of the outdoor heat exchanger 104, and is used to throttle and cool the refrigerant, and the indoor throttling element 202 is located upstream of the inlet of the indoor heat exchanger 201. In the heating state, the indoor heat exchanger 201 serves as a condenser, and the outdoor heat exchanger 104 serves as an evaporator. The cooling state and the heating state are switched by the four-way reversing valve 103. The liquid storage container 107 can be a liquid storage tank, etc., which is used to temporarily store the refrigerant in the refrigerant circulation loop.

[0077] The second end of the liquid inlet branch 1 is connected to the medium-pressure side pipeline to collect the refrigerant from the medium-pressure side pipeline into the liquid storage container 107 under different working modes. When collecting liquid, a pressure difference needs to be established at both ends of the liquid inlet branch 1 so that the pressure at the first end of the liquid inlet branch 1 is less than the pressure at the second end, so as to utilize the pressure difference to allow at least part of the refrigerant in the refrigerant circulation loop to enter the liquid storage container 107.

[0078] The second end of the drainage branch 2 can be connected to one, two or three of the low-pressure side pipeline, medium-pressure side pipeline and high-pressure side pipeline of the external unit system as needed, so that the refrigerant in the liquid storage container 107 can be discharged to different pressure sides, which is conducive to realizing different drainage modes. When draining, the pressure at the first end of the drainage branch 2 is greater than the pressure at the second end, so that the pressure difference can be used to discharge at least part of the refrigerant in the liquid storage container 107 into the refrigerant circulation loop.

[0079] For example, the high-pressure side pipeline can be called the first pressure side pipeline, the medium-pressure side pipeline can be called the second pressure side pipeline, and the low-pressure side pipeline can be called the third pressure side pipeline, wherein the first pressure interval is higher than the second pressure interval, and the second pressure interval is higher than the third pressure interval.

[0080] For example, the refrigerant circulation loop also includes a four-way reversing valve 103 and a gas-liquid separator 106. The four-way reversing valve 103 is used to switch between the cooling mode and the heating mode. The gas-liquid separator 106 is arranged on the pipeline between the four-way reversing valve 103 and the suction port of the compressor 101.

[0081] For such a system, Figure 2As shown, in the cooling mode, the high-pressure side pipeline is the pipeline between the exhaust port of the compressor 101 and the condenser (external heat exchanger 104), the medium-pressure side pipeline is the pipeline between the condenser (external heat exchanger 104) and the evaporator (internal heat exchanger 201), and the low-pressure side pipeline includes: from the evaporator (internal heat exchanger 201) through the four-way reversing valve 103 to the inlet of the gas-liquid separator 106, and the pipeline between the outlet of the gas-liquid separator 106 and the air inlet of the compressor 101.

[0082] like Figure 3 As shown, in the heating mode, the high-pressure side pipeline is the pipeline between the exhaust port of the compressor 101 and the condenser (indoor heat exchanger 201), the medium-pressure side pipeline is the pipeline between the condenser (indoor heat exchanger 201) and the evaporator (outdoor heat exchanger 104), and the low-pressure side pipeline includes: from the evaporator (outdoor heat exchanger 104) through the four-way reversing valve 103 to the inlet of the gas-liquid separator 106, and the pipeline between the outlet of the gas-liquid separator 106 and the air inlet of the compressor 101.

[0083] This embodiment adds a liquid storage container 107 to the air-conditioning system, and is connected to the medium-pressure side pipeline of the system through a liquid inlet valve 108 that can realize the on-off function, and is connected to at least one of the low-pressure side pipeline, medium-pressure side pipeline and high-pressure side pipeline in the system through a liquid discharge valve 109 that can realize the on-off function. On the basis of realizing the conventional refrigerant mode and the heating mode, the excess refrigerant in the refrigerant circulation loop can be collected from a specific pressure side by using the pressure difference according to the actual heat exchange demand of the air-conditioning system, or the refrigerant in the liquid storage container 107 can be discharged into the refrigerant circulation loop for replenishment according to the actual refrigerant demand, so as to achieve the best heat exchange effect and improve the heat exchange efficiency of the system, thereby improving the working energy efficiency of the air-conditioning system.

[0084] Moreover, the excess refrigerant collected from the medium-pressure side pipeline also has a relatively large pressure, so that the refrigerant can be smoothly stored in the liquid storage container 107. In the refrigeration mode and the defrost mode, the connection position of the second end of the liquid inlet branch 1 is located upstream of the gas-liquid separator 106. The excess refrigerant can be collected by relying solely on the liquid storage container 107 to achieve the adjustment of the amount of circulating refrigerant. There is no need to combine with the gas-liquid separator to store the refrigerant in the gas-liquid separator first. When needed, the refrigerant is allowed to enter the liquid storage container from the gas-liquid separator and then be released from the liquid storage container, thereby improving the heat exchange efficiency.

[0085] In addition, the refrigerant adjustment function and the refrigerant transfer function can be simultaneously realized through the same liquid storage container 107, which simplifies the system and pipeline structure, reduces costs, and improves product space utilization.

[0086] In the refrigerant adjustment function, the refrigerant is stored and released through the liquid storage container 107, and the amount of refrigerant in different operating modes is controlled, so that the system refrigerant circulation amount is consistent with the refrigerant demand in different operating modes, thereby achieving the best heat exchange effect.

[0087] In the refrigerant transfer function, the problem of system refrigerant accumulating on the outdoor low-pressure side after defrosting can be solved. The liquid refrigerant is directly stored in the liquid storage container 107 during defrosting. After the defrosting is completed and switched to the heating mode, the stored refrigerant is released into the refrigerant circulation loop to participate in the heating cycle, which is more conducive to reducing the time for the heating capacity to recover to the maximum output after defrosting and improving the heating capacity.

[0088] In the traditional solution, the refrigerant will be stored in the gas-liquid separator during the defrosting process. Often, more liquid refrigerant will be stored in the gas-liquid separator after defrosting. After the defrosting is completed and the heating mode is entered, the liquid refrigerant will be transferred to the liquid storage container. It takes a long time to transfer the refrigerant.

[0089] In some embodiments, Figure 1 As shown, the liquid storage container 107 also has a pressure regulating port C, and the air conditioning system also includes:

[0090] The pressure relief branch 3 is provided with a balancing valve 111 with an on state and an off state. The first end of the pressure relief branch 3 is connected to the pressure regulating port C. For example, the second end of the pressure relief branch 3 is connected to the low-pressure side pipeline, which is more conducive to liquid discharge, or it can also be connected to the medium-pressure side pipeline or other positions, as long as the pressure at the connected position is lower than the pressure in the liquid storage container 107;

[0091] When the balancing valve 111 is in the on state, the pressure in the liquid storage container 107 is released through the pressure relief branch 3 .

[0092] Specifically, the refrigerant circulation loop also includes a four-way reversing valve 103 and a gas-liquid separator 106. The four-way reversing valve 103 is used to switch between the cooling mode and the heating mode, and the gas-liquid separator 106 is arranged on the pipeline between the four-way reversing valve 103 and the air intake of the compressor 101. Based on this, the second end of the pressure relief branch 3 is connected to the pipeline at the inlet of the gas-liquid separator 106, and the gaseous refrigerant discharged through the pressure relief branch 3 can first enter the gas-liquid separator 106 for gas-liquid separation, and then the gas enters the compressor 101 to prevent the compressor 101 from sucking liquid with liquid and causing liquid hammer.

[0093] This embodiment provides a pressure relief branch 3 for the liquid storage container 107. When the pressure in the liquid storage container 107 is high and liquid cannot be collected normally, the pressure in the liquid storage container 107 can be released to the low-pressure side pipeline by connecting the balancing valve 111, thereby ensuring a pressure difference at both ends of the liquid inlet valve 108, which is beneficial to the subsequent smooth liquid collection and realizes efficient storage of the refrigerant.

[0094] In some embodiments, Figure 8As shown, the second end of the drain branch 2 is configured to be connected to the low-pressure side pipeline in the cooling mode, and the drain valve 109 is configured to be in the on state in the cooling mode.

[0095] Specifically, the second end of the liquid discharge branch 2 may be connected between the four-way reversing valve 103 and the inlet of the gas-liquid separator 106 .

[0096] This embodiment connects the second end of the first drain branch 2 to the low-pressure side pipeline in the cooling mode, which can minimize the pressure at the second end of the drain branch 2, facilitate the smooth release of the refrigerant from the liquid storage container 107, and the discharged refrigerant merges with the refrigerant flowing out of the evaporator, increasing the amount of refrigerant in the low-pressure side pipeline, which can improve the heat exchange capacity of the air-conditioning system in the cooling mode.

[0097] In some embodiments, Figure 4 and Figure 5 As shown, the liquid inlet valve 108 is in the on state in the defrost mode, the liquid discharge valve 109 is in the on state in the initial stage of switching to the heating mode after the defrost ends, and the second end of the liquid discharge branch 2 is configured to be connected to the high-pressure side pipeline in the heating mode.

[0098] Among them, Figure 4 As shown, this is the heating defrost mode, the liquid inlet valve 108 is in the on state, the liquid discharge valve 109 is in the off state, and the excess refrigerant in the refrigerant circulation loop is stored in the liquid storage container 107 from the medium-pressure side pipeline position during the defrost process to solve the problem of system refrigerant accumulating on the outdoor low-pressure side after defrosting.

[0099] like Figure 5 As shown, at the initial stage of entering the heating mode after the defrost mode ends, the drain valve 109 is in the on state and the inlet valve 108 is in the off state. The high-pressure refrigerant on the exhaust side can be used to establish a pressure difference at both ends of the drain branch 2, and the liquid refrigerant in the liquid storage container 107 can be discharged to the high-pressure side pipeline, directly and quickly participating in the heating cycle, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity.

[0100] This embodiment configures the second end of the drain branch 2 to be connected to the high-pressure side pipeline in the heating mode, which can better realize the refrigerant transfer function and enable the air-conditioning system to achieve better refrigerant adjustment and transfer effects. During the defrosting process, the refrigerant can be directly stored in the liquid storage container 107 without the need to be combined with the gas-liquid separator 106 to realize refrigerant storage. At the initial stage of entering the heating mode after the defrosting mode ends, the liquid refrigerant in the liquid storage container 107 is discharged to the high-pressure side pipeline, directly and quickly participating in the heating cycle, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity.

[0101] In some embodiments, Figure 1As shown, the liquid storage container 107 also has a pressure regulating port C, and the air conditioning system also includes:

[0102] A pressurizing branch 4 is provided with a pressurizing valve 110 having an on state and an off state, and a first end of the pressurizing branch 4 is connected to a pressure regulating port C;

[0103] When the pressurizing valve 110 is in the on state, the high-pressure side pipeline pressurizes the liquid storage container 107 .

[0104] Preferably, the second end of the pressurizing branch 4 is connected to the high-pressure side pipeline to provide more sufficient pressure in the liquid storage container to facilitate smooth discharge. Optionally, the second end of the pressurizing branch 4 can also be connected to the medium-pressure side pipeline or a pipeline at another position, as long as the pressure is higher than that in the liquid storage container 107.

[0105] Specifically, the second end of the pressurizing branch 4 is connected to the pipeline between the exhaust port of the compressor 101 and the four-way reversing valve 103 .

[0106] This embodiment sets a pressurizing branch 4 for the liquid storage container 107. When the pressure in the liquid storage container 107 is low and the liquid cannot be discharged normally, the pressurizing valve 110 can be turned on to lead the high pressure of the exhaust port of the compressor 101 into the liquid storage container 107, thereby ensuring that a pressure difference is established at both ends of the discharge valve, which is conducive to smooth discharge of the liquid, so that the refrigerant in the liquid storage container 107 can be discharged efficiently, the discharge efficiency can be improved, the amount of refrigerant remaining in the liquid storage container 107 can be reduced, the larger refrigerant demand in the system can be met, and the heat exchange effect can be optimized.

[0107] In some embodiments, Fig.12 As shown, the air conditioning system also includes an auxiliary drain branch 5, on which an auxiliary drain valve 113 with an on state and an off state is provided. The first end of the auxiliary drain branch 5 is connected to the liquid outlet B, and the second end of the auxiliary drain branch 5 is connected to the low-pressure side pipeline.

[0108] Specifically, the second end of the auxiliary drain branch 5 is connected to the pipeline between the four-way reversing valve 103 and the inlet of the gas-liquid separator 106. The liquid refrigerant discharged through the auxiliary drain branch 5 can first enter the gas-liquid separator 106 for gas-liquid separation, and then the gas enters the compressor 101 to prevent liquid hammer caused by the compressor 101 sucking in liquid.

[0109] This embodiment can be used in any working mode of the air-conditioning system. When it is necessary to discharge the refrigerant in the liquid storage container 107 more quickly, the auxiliary drain valve 113 is also in an on state. Through the auxiliary drain branch 5 and the drain branch 2, the liquid refrigerant in the liquid storage container 107 is discharged more quickly to the refrigerant circulation loop to participate in the heat exchange cycle, thereby improving the heat exchange capacity.

[0110] In some embodiments, Figure 1 As shown, the air-conditioning system also includes a unloading branch 6, a first end of the unloading branch 6 is connected to the liquid inlet A, a second end of the unloading branch 6 is connected to the low-pressure side pipeline, and an unloading valve 112 having an on state and an off state is provided on the unloading branch 6. The unloading valve 112 is configured to be in an on state when the pressure in the liquid storage container 107 is higher than a preset safety threshold.

[0111] Specifically, the second end of the unloading branch 6 is connected to the pipeline between the four-way reversing valve 103 and the inlet of the gas-liquid separator 106. The liquid refrigerant discharged through the unloading branch 6 can first enter the gas-liquid separator 106 for gas-liquid separation, and then the gas enters the compressor 101 to prevent the compressor 101 from sucking in liquid and causing liquid hammer. Optionally, the first end of the unloading branch 6 can also be connected to other positions in the liquid storage container 107.

[0112] This embodiment can release the pressure to the low-pressure side pipeline through the unloading valve 112 when the refrigerant pressure in the liquid storage container 107 exceeds a preset safety threshold, thereby facilitating the release of the pressure in the liquid storage container 107 and improving the safety of the air-conditioning system.

[0113] In some embodiments, the liquid inlet A and the pressure regulating port C are disposed in the upper region of the liquid storage container 107 , and the liquid outlet B is disposed in the lower region of the liquid storage container 107 .

[0114] Among them, the liquid storage container 107 includes a top wall, a bottom wall and a side wall, and can be, for example, cylindrical or prismatic. The "upper area" includes the area above the top wall and the side wall, and the "lower area" includes the area below the bottom wall and the side wall. For example, the liquid inlet A can be arranged on the top wall, and after the refrigerant is introduced through the liquid inlet pipeline, it can fall directly into the bottom of the liquid storage container 107 from above, and gas-liquid separation is not easy to occur; the liquid outlet B can be arranged in the bottom area of ​​the side wall, and when the amount of liquid storage is small, the refrigerant inside the liquid storage container 107 can also be discharged smoothly; the pressure regulating port C is arranged in the upper area of ​​the side wall, which is convenient for pressure regulation by discharging gaseous refrigerant or passing high-pressure gaseous refrigerant. Optionally, the liquid inlet A can also be arranged in the lower area.

[0115] In this embodiment, the liquid inlet A can be arranged in the upper area of ​​the liquid storage container 107. After the refrigerant is introduced through the liquid inlet pipeline, it can fall directly from the top to the bottom of the liquid storage container 107 with less resistance, and the liquid can be collected smoothly. The pressure regulating port C is arranged in the upper area of ​​the liquid storage container 107, which is convenient for adjusting the pressure inside the liquid storage container 107 by releasing the gaseous refrigerant or introducing the high-pressure gaseous refrigerant. The liquid outlet B is arranged in the lower area of ​​the liquid storage container 107, so that the refrigerant inside the liquid storage container 107 can be discharged smoothly when the amount of stored liquid is small.

[0116] In some embodiments, Figure 1As shown, the refrigerant circulation circuit also includes a four-way reversing valve 103 and a gas-liquid separator 106. The four-way reversing valve 103 is used to switch between the cooling mode and the heating mode. The gas-liquid separator 106 is arranged on the pipeline between the four-way reversing valve 103 and the air intake port of the compressor 101;

[0117] The air conditioning system further includes a pressure relief branch 3 and a pressure increase branch 4, wherein the first ends of the pressure relief branch 3 and the pressure increase branch 4 are each connected to the pressure regulating port C of the liquid storage container 107, the second end of the pressure relief branch 3 is connected to the low-pressure side pipeline, and the second end of the pressure increase branch 4 is connected to the high-pressure side pipeline;

[0118] The second end of the discharge branch 2 is connected to the pipeline between the four-way reversing valve 103 and the evaporator, the second end of the pressurization branch 4 is connected to the pipeline between the exhaust port of the compressor 101 and the four-way reversing valve 103, and the second end of the pressure relief branch 3 is connected between the inlet of the gas-liquid separator 106 and the four-way reversing valve 103.

[0119] This embodiment is provided with a liquid inlet valve 108, a liquid discharge valve 109, a balancing valve 111 and a pressurizing valve 110. Through the cooperation of these four valves, different working modes can be realized, and the refrigerant adjustment and transfer functions are provided. In the conventional scheme of setting two liquid storage containers, seven valves need to be provided.

[0120] The second end of the drain branch 2 is connected to the pipeline between the four-way reversing valve 103 and the evaporator. When draining in the cooling mode, the refrigerant discharged from the drain branch 2 can flow to the four-way reversing valve 103 together with the refrigerant flowing out of the evaporator, and then enter the gas-liquid separator 106 for separation and then replenish the gaseous refrigerant to the compressor 101; when draining in the heating mode, the refrigerant flowing out of the compressor 101 through the four-way reversing valve 103 is combined with the refrigerant discharged from the drain branch 2 and can enter the condenser for heat exchange, thereby achieving a larger heat exchange capacity.

[0121] The second end of the pressurizing branch 4 is connected to the pipeline between the exhaust port of the compressor 101 and the four-way reversing valve 103. The larger pressure at the exhaust port of the compressor 101 can be used to pressurize the liquid storage container 107 so that the refrigerant in the liquid storage container 107 can be discharged smoothly.

[0122] The second end of the pressure relief branch 3 is connected between the inlet of the gas-liquid separator 106 and the four-way reversing valve 103. When the pressure in the liquid storage container 107 is too high to continue collecting liquid, the gaseous refrigerant discharged through the pressure relief branch 3 can first enter the gas-liquid separator 106 for gas-liquid separation, and then the gas can enter the compressor 101 to prevent liquid hammer caused by the compressor 101 sucking in liquid.

[0123] In some embodiments, the liquid storage container 107 is built into the outdoor unit assembly 10 .

[0124] In this embodiment, the liquid storage container 107 is built into the outdoor unit assembly 10, which does not require additional site space during engineering installation, and can also reduce the installation difficulty of the entire air conditioning system, without the need to install the liquid storage container 107 as a separate accessory. Optionally, the liquid storage container 107 can be installed between the outdoor unit assembly 10 and the indoor unit assembly 20.

[0125] Secondly, the present disclosure provides a control method for an air conditioning system based on the above embodiment, which in some embodiments includes:

[0126] Liquid collecting step: the liquid inlet valve 108 is turned on, and the pressure at the first end of the liquid inlet branch 1 is lower than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container 107;

[0127] Discharge step: When the refrigerant in the liquid storage container 107 needs to be discharged to the refrigerant circulation loop, the discharge valve 109 is turned on, and the pressure at the first end of the discharge branch 2 is greater than the pressure at the second end.

[0128] When the air conditioning system is in load conversion or mode conversion, the load conversion means that the number of indoor units in the multi-split system changes. Since the air conditioning operation state changes greatly, the refrigerant in the refrigerant circulation loop can be adapted to the working demand through the liquid collection mode and the liquid discharge mode. When the air conditioning system has just switched from the defrosting mode to the heating state for a period of time, it is necessary to speed up the liquid discharge to facilitate the rapid entry of liquid refrigerant into the system to participate in the circulation.

[0129] The air-conditioning system control method of this embodiment is connected to the medium-pressure side pipeline of the system through an inlet valve 108 that can realize the on-off function, and is connected to at least one of the low-pressure side pipeline, the medium-pressure side pipeline and the high-pressure side pipeline in the system through a drain valve 109 that can realize the on-off function. On the basis of realizing the conventional refrigerant mode and the heating mode, the pressure difference can be used to collect excess refrigerant in the refrigerant circulation loop from a specific pressure side according to the actual heat exchange demand of the air-conditioning system, or the refrigerant in the liquid storage container 107 can be discharged into the refrigerant circulation loop for replenishment according to the actual refrigerant demand, so as to achieve the best heat exchange effect and improve the heat exchange efficiency of the system, thereby improving the working energy efficiency of the air-conditioning system.

[0130] Moreover, the excess refrigerant collected from the medium-pressure side pipeline also has a relatively large pressure, so that the refrigerant can be smoothly stored in the liquid storage container 107. In the refrigeration mode and the defrost mode, the connection position of the second end of the liquid inlet branch 1 is located upstream of the gas-liquid separator 106. The excess refrigerant can be collected by relying solely on the liquid storage container 107 to achieve the adjustment of the amount of circulating refrigerant. There is no need to combine with the gas-liquid separator to store the refrigerant in the gas-liquid separator first. When needed, the refrigerant is allowed to enter the liquid storage container from the gas-liquid separator and then be released from the liquid storage container, thereby improving the heat exchange efficiency.

[0131] In some embodiments, the air conditioning system further includes a pressure relief branch 3 and a pressurization branch 4, the pressure relief branch 3 is provided with a balancing valve 111, the pressurization branch 4 is provided with a pressurization valve 110, the first ends of the pressure relief branch 3 and the pressurization branch 4 are respectively connected to the pressure regulating port C of the liquid storage container 107, the second end of the pressure relief branch 3 can be connected to the low-pressure side pipeline or the medium-pressure side pipeline, and the second end of the pressurization branch 4 is connected to the high-pressure side pipeline; the control method also includes:

[0132] In the liquid collecting step, the balance valve 111 is turned on to reduce the pressure in the liquid storage container 107;

[0133] In the liquid discharge step, the pressurizing valve 110 is turned on to increase the pressure in the liquid storage container 107 .

[0134] In the liquid collecting step of this embodiment, when the pressure in the liquid storage container 107 is too high to collect liquid normally, the pressure in the liquid storage container 107 is released to the low-pressure side pipeline by connecting the balancing valve 111, ensuring that a pressure difference is established at both ends of the liquid inlet valve 108, which is conducive to further smooth liquid collection and efficient storage of refrigerant. In the liquid discharging step, when the pressure in the liquid storage container 107 is too low to discharge liquid normally, the pressurizing valve 110 is connected, and the high pressure at the exhaust port of the compressor 101 is introduced into the liquid storage container 107, ensuring that a pressure difference is established at both ends of the liquid discharging valve, which is conducive to smooth liquid discharging, efficient discharge of the refrigerant in the liquid storage container 107, improving the liquid discharging efficiency, reducing the amount of refrigerant remaining in the liquid storage container 107, meeting the larger refrigerant demand in the system, and optimizing the heat exchange effect.

[0135] In some embodiments, Figure 6 , Figure 7 and Fig. 9 , Fig.10 As shown, in the refrigerant adjustment function in the cooling mode and the heating mode, the liquid collection step includes:

[0136] The liquid inlet valve 108 is in an on state, and when the pressure difference across the liquid inlet valve 108 is less than a preset threshold, the balancing valve 111 is in an on state, and the liquid discharge valve 109 and the pressurizing valve 110 are both in an off state.

[0137] in, Figure 6 Schematic diagram of storing refrigerant in the cooling mode in the refrigerant transfer function. The liquid inlet valve 108 is in the on state. A part of the liquid refrigerant flowing out of the outdoor heat exchanger 104 enters the liquid storage container 107 through the liquid inlet valve 108 to complete the liquid collection in the cooling mode. Figure 7As shown, when the pressure in the liquid storage container 107 is high, making the pressure difference at both ends of the liquid inlet valve 108 small, the balancing valve 111 is in the on state, and the second end of the balancing valve 111 is connected to the low-pressure side pipeline, which can realize the internal pressure relief of the liquid storage container 107 and make the refrigerant storage process proceed smoothly.

[0138] Fig. 9 Schematic diagram of refrigerant storage in heating mode in the refrigerant transfer function. The liquid inlet valve 108 is in the on state. A portion of the liquid refrigerant flowing out of the indoor heat exchanger 201 enters the liquid storage container 107 through the liquid inlet valve 108 to complete the liquid collection in heating mode. Fig.10 As shown, when the pressure in the liquid storage container 107 is high, making the pressure difference at both ends of the liquid inlet valve 108 small, the balancing valve 111 is in the on state, and the second end of the balancing valve 111 is connected to the low-pressure side pipeline, which can realize the internal pressure relief of the liquid storage container 107 and make the refrigerant storage process proceed smoothly.

[0139] When collecting liquid in the cooling mode or the heating mode, this embodiment enables the liquid inlet valve 108 to be in the on state, so that the refrigerant in the medium-pressure side pipeline can enter the liquid storage container 107 to collect liquid, and when the pressure in the liquid storage container 107 is high and liquid cannot be collected normally, by enabling the balancing valve 111 to be in the on state, the pressure in the liquid storage container 107 can be discharged to the low-pressure side pipeline through the pressure relief branch 3, ensuring that a pressure difference is established at both ends of the liquid inlet valve 108, which is conducive to further smooth liquid collection and efficient storage of the refrigerant.

[0140] In some embodiments, Figure 8 As shown, the second end of the drain branch 2 is configured to communicate with the low-pressure side pipeline in the cooling mode;

[0141] In the refrigerant adjustment function in the cooling mode, the draining step includes: making the drain valve 109 in an on state, and the inlet valve 108 and the balance valve 111 in an off state.

[0142] In the refrigeration discharge mode, this embodiment discharges liquid to the low-pressure side pipeline, so the discharge valve 109 alone can be used to discharge liquid, and the discharge function can be achieved, which can simplify the control method.

[0143] In some embodiments, in the refrigerant adjustment function in the cooling mode, the liquid discharge step further includes: when the internal pressure of the liquid storage container 107 drops to the same level as the low-pressure side pipeline, the pressurizing valve 110 is in an on state. In this process, the balancing valve 111 and the liquid inlet valve 108 are both in an off state.

[0144] The second end of the drain branch 2 in this embodiment is connected to the low-pressure side pipeline. After the drain valve 109 is opened, the refrigerant can enter the system circulation. When the internal pressure of the liquid storage container 107 drops to a point where it cannot be discharged, the internal pressure of the liquid storage container 107 is increased by opening the pressurizing valve 110 for a preset time, so that the refrigerant can continue to be discharged, and the refrigerant can be discharged smoothly in the refrigeration mode of the refrigerant adjustment function.

[0145] In some embodiments, Fig.11 As shown, the second end of the drain branch 2 is configured to communicate with the high-pressure side pipeline in the heating mode;

[0146] In the refrigerant adjustment function under the heating mode, the draining step includes: putting the pressurizing valve 110 in an on state to increase the pressure inside the liquid storage container 107 to the pressure at the second end of the pressurizing branch 4, and putting the draining valve 109 in an on state.

[0147] Preferably, the pressure-increasing valve 110 is first turned on to raise the pressure inside the liquid storage container 107 to the pressure at the second end of the pressure-increasing branch 4, and then the liquid discharge valve 109 is opened to facilitate reaching the pressure required for liquid discharge; or the pressure-increasing valve 110 and the liquid discharge valve 109 can be opened at the same time. In this process, the liquid inlet valve 108 and the balance valve 111 are turned off;

[0148] Specifically, the pressure at the exhaust port of the compressor 101 is marked as the first pressure point P1, and the pressure downstream of the drain valve 109 is marked as the second pressure point P2. In the heating mode, P1>P2. In this state, the pressurizing valve 110 is opened, and the pressure P0 inside the liquid storage container 107 is P1>P2. Opening the first drain valve 115 can discharge the refrigerant in the liquid storage container 107.

[0149] When discharging liquid in the heating mode in the refrigerant adjustment function of this embodiment, since the second end of the discharge branch 2 is connected to the high-pressure side pipeline, by turning on the pressurizing valve 110 during discharge, the high-pressure pipeline at the exhaust port of the compressor 101 can be used to pressurize the interior of the liquid storage container 107, thereby achieving smooth discharge in the heating mode.

[0150] Optionally, in the heating mode of the refrigerant adjustment function, the pressurizing valve 110 is first placed in an on state, and when the pressure inside the liquid storage container 107 rises to the pressure at the second end of the pressurizing branch 4, the pressurizing valve 110 is switched to an off state; thereafter, the compressor 101 is reduced in frequency or stopped, and at this time, the drain valve 109 is placed in an on state.

[0151] This control method first increases the pressure in the liquid storage container 107 through the pressure-boosting valve 110 and maintains the pressure. Since the second end of the discharge branch 2 is connected to the high-pressure side pipeline, it is difficult to discharge a large amount of refrigerant, and a lot of refrigerant will remain in the liquid storage container 107. By reducing the frequency or stopping the compressor 101, the pressure at the second end of the discharge branch 2 can be reduced, so that the refrigerant in the liquid storage container 107 can be discharged smoothly and the discharge amount of the refrigerant can be increased.

[0152] In some embodiments, the second end of the drain branch 2 is configured to communicate with the high-pressure side pipeline in the heating mode, and in the refrigerant transfer function,

[0153] During the defrosting process, Figure 4 and Figure 5 As shown, the liquid collecting step includes: making the liquid inlet valve 108 in an on state, and making the liquid discharge valve 109, the balancing valve 111 and the pressurizing valve 110 in an off state; and / or

[0154] In the initial stage of switching to heating mode after defrosting, the pressurizing valve 110 is first turned on to increase the pressure inside the liquid storage container 107 to the pressure at the second end of the pressurizing branch 4, and then the drain valve 109 is turned on.

[0155] Among them, Figure 4 As shown, this is the heating defrost mode, the liquid inlet valve 108 is in the on state, the liquid discharge valve 109 is in the off state, and the excess refrigerant in the refrigerant circulation loop is stored in the liquid storage container 107 from the medium-pressure side pipeline position during the defrost process to solve the problem of system refrigerant accumulating on the outdoor low-pressure side after defrosting.

[0156] like Figure 5 As shown, at the initial stage of entering the heating mode after the defrost mode ends, the drain valve 109 is in the on state and the inlet valve 108 is in the off state. The high-pressure refrigerant on the exhaust side can be used to establish a pressure difference at both ends of the drain branch 2, and the liquid refrigerant in the liquid storage container 107 can be discharged to the high-pressure side pipeline, directly and quickly participating in the heating cycle, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity.

[0157] This embodiment configures the second end of the drain branch 2 to be connected to the high-pressure side pipeline in the heating mode, which can better realize the refrigerant transfer function and enable the air-conditioning system to achieve better refrigerant adjustment and transfer effects. During the defrosting process, the refrigerant can be directly stored in the liquid storage container 107 without the need to be combined with the gas-liquid separator 106 to realize refrigerant storage. At the initial stage of entering the heating mode after the defrosting mode ends, the liquid refrigerant in the liquid storage container 107 is discharged to the high-pressure side pipeline, directly and quickly participating in the heating cycle, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity.

[0158] The following is combined with Figures 1 to 11 The embodiments given in the specification specifically illustrate the working principle of the air conditioning system of the present disclosure. The valves in the above embodiments can all be solenoid valves and controlled by a controller.

[0159] The air conditioning system includes a compressor 101, an external heat exchanger 104, an internal heat exchanger 201, a liquid inlet valve 108, a liquid storage container 107, a gas-liquid separator 106, a four-way reversing valve 103, a drain valve 109, a pressurizing valve 110 and a balancing valve 111. Further, an oil separator 102 may be provided downstream of the compressor 101, the inlet of the oil separator 102 is communicated with the exhaust port of the compressor 101, the air outlet is communicated with the four-way reversing valve 103, and the oil outlet is communicated with the air inlet of the compressor 101. The air conditioning system also includes an unloading valve 112, the first end of the unloading valve 112 is connected to the liquid inlet branch 1 between the liquid inlet valve 108 and the liquid inlet A, the second end of the unloading valve 112 is connected to the inlet of the gas-liquid separator 106 and the pipeline between the four-way reversing valve 103, and is used to release the pressure when the pressure of the liquid inlet branch 1 exceeds the safety threshold.

[0160] The air conditioning system of this embodiment has a conventional cooling mode and a defrosting mode:

[0161] like Figure 2 In the conventional refrigeration mode and defrost mode shown, when there is no need to adjust the amount of circulating refrigerant in the system, the inlet valve 108, the drain valve 109, the pressurizing valve 110 and the balancing valve 111 are all in the disconnected state. The refrigerant is discharged from the compressor 101, passes through the oil separator 102 and the four-way reversing valve 103, enters the outdoor heat exchanger 104 for condensation, and then passes through the outdoor throttling element 105 and the indoor throttling element 202 for throttling, enters the indoor heat exchanger 201 for evaporation, and finally flows through the four-way reversing valve 103 into the gas-liquid separator 106 and returns to the air intake of the compressor 101.

[0162] like Figure 3 In the conventional heating mode shown, when there is no need to adjust the amount of circulating refrigerant in the system, the inlet valve 108, the drain valve 109, the pressurizing valve 110 and the balancing valve 111 are all in the disconnected state. The refrigerant is discharged from the compressor 101, passes through the oil separator 102 and the four-way reversing valve 103, enters the indoor heat exchanger 201 for condensation, and then passes through the indoor throttling element 202 and the outdoor throttling element 105 for throttling, enters the outdoor heat exchanger 104 for evaporation, and finally flows through the four-way reversing valve 103 into the gas-liquid separator 106 and returns to the air intake of the compressor 101. For example, the throttling element can be an electronic expansion valve or a capillary tube.

[0163] In addition, the air conditioning system also has the function of refrigerant transfer and adjustment:

[0164] 1. Refrigerant transfer function:

[0165] like Figure 4 As shown, the inlet valve 108 is in the on state, and the pressurizing valve 110, the balancing valve 111, and the drain valve 109 are closed. The position connected to the second end of the inlet valve 108 is the medium-pressure side of the system. When this valve is in the on state, the refrigerant flowing out of the outdoor heat exchanger 104 and the outdoor throttling element 105, a part of the excess refrigerant is stored in the liquid storage container 107 through the inlet valve 108, and the storage of the refrigerant in the defrosting process is completed to solve the problem of the system refrigerant being stored on the outdoor low-pressure side after defrosting, and the rest continues to flow to the inner side to maintain the defrosting circulation flow path.

[0166] Optionally, when the internal pressure is high and the pressure difference across the liquid inlet valve 108 is small, the balancing valve 111 is in an on state, and the position connected to the second end of the balancing valve 111 is the low-pressure side of the system, thereby achieving internal pressure relief in the liquid storage container 107 .

[0167] like Figure 5 As shown, at the initial stage of entering the heating mode after the defrosting mode ends, the pressurizing valve 110 is first turned on to increase the pressure inside the liquid storage container 107 to the pressure at the second end of the pressurizing branch 4, and then the drain valve 109 is opened; during this process, the liquid inlet valve 108 and the balance valve 111 are in the disconnected state. Thus, the high-pressure refrigerant discharged from the oil separator 102 can be used to establish a pressure difference at both ends of the drain branch 2, and the liquid refrigerant in the liquid storage container 107 can be discharged to the high-pressure side pipeline, directly and quickly participating in the heating cycle, reducing the time for the heating capacity to recover to the maximum output after defrosting, and improving the heating capacity.

[0168] 2. Refrigerant adjustment function:

[0169] like Figure 6 As shown, it is a schematic diagram of storing refrigerant in the cooling mode of the refrigerant adjustment function. In this mode, the liquid inlet valve 108 is open; the liquid discharge valve 109, the pressurizing valve 110, and the balancing valve 111 are closed. A part of the medium-pressure refrigerant flowing out of the external heat exchanger 104 and the external throttling element 105 enters the liquid storage container 107 through the liquid inlet valve 108, so that the excess refrigerant is stored in the liquid storage container 107, reducing the amount of circulating refrigerant in the system.

[0170] On this basis, if Figure 7 As shown, as the refrigerant storage amount in the liquid storage container 107 increases, the internal pressure of the liquid storage container 107 gradually rises. When the pressure difference across the liquid inlet valve 108 is reduced to the point where the liquid inlet power is insufficient, the balancing valve 111 needs to be opened synchronously to release the pressure so that the refrigerant can continue to be stored in the liquid storage container 107.

[0171] like Figure 8, which is a schematic diagram of releasing refrigerant in the cooling mode of the refrigerant adjustment function. In this mode, the drain valve 109 is opened, and the pressurizing valve 110, the inlet valve 108, and the balancing valve 111 are closed. The refrigerant in the liquid storage container 107 can return to the system through the drain valve 109 to participate in the circulation.

[0172] like Fig. 9 As shown, it is the flow path for storing refrigerant in the heating mode of the refrigerant adjustment function. In this mode, the liquid inlet valve 108 is open; the liquid discharge valve 109, the pressurizing valve 110, and the balancing valve 111 are closed. A part of the medium-pressure refrigerant flowing out of the indoor heat exchanger 201 and the indoor throttling element 202 enters the liquid storage container 107 through the liquid inlet valve 108, so that the excess refrigerant is stored in the liquid storage container 107, reducing the amount of refrigerant circulating in the system. The rest of the refrigerant continues to flow to the outdoor heat exchanger 104 to maintain the circulation flow path.

[0173] exist Fig. 9 On the basis of Fig.10 As shown, as the refrigerant storage amount in the liquid storage container 107 increases, the internal pressure of the liquid storage container 107 gradually rises. When the pressure difference across the liquid inlet valve 108 is reduced to the point where the liquid inlet power is insufficient, the balancing valve 111 needs to be opened synchronously to release the pressure so that the refrigerant can continue to be stored in the liquid storage container 107.

[0174] like Fig.11 As shown, it is the flow path for releasing the refrigerant in the heating mode of the refrigerant adjustment function. In this mode, the drain valve 109 and the pressurizing valve 110 are opened; the inlet valve 108 and the balancing valve 111 are closed. The high-temperature and high-pressure refrigerant discharged from the oil separator 102 enters the liquid storage container 107 through the pressurizing valve 110, so that the refrigerant in the liquid storage container 107 is discharged through the drain valve 109.

[0175] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. An air conditioning system, characterized in that: include: A refrigerant circulation loop is provided with a compressor (101), an evaporator and a condenser, a high-pressure side pipeline is between the exhaust port of the compressor (101) and the condenser, a medium-pressure side pipeline is between the condenser and the evaporator, and a low-pressure side pipeline is between the evaporator and the air intake port of the compressor (101); A liquid storage container (107), used for storing refrigerant and having a liquid inlet (A) and a liquid outlet (B); A liquid inlet branch (1) is provided with a liquid inlet valve (108) having an on state and an off state, a first end of the liquid inlet branch (1) being in communication with the liquid inlet port (A), and a second end of the liquid inlet branch (1) being in communication with the medium-pressure side pipeline; and a liquid discharge branch (2) on which a liquid discharge valve (109) having an on state and an off state is provided, a first end of the liquid discharge branch being in communication with the liquid outlet (B), and a second end of the liquid discharge branch being in communication with the refrigerant circulation circuit; Wherein, when the liquid inlet valve (108) is in the on state, the pressure at the first end of the liquid inlet branch (1) is lower than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container (107) by utilizing the pressure difference; when the liquid discharge valve (109) is in the on state, the pressure at the first end of the liquid discharge branch (2) is higher than the pressure at the second end, so that the refrigerant in the liquid storage container (107) is discharged to the refrigerant circulation loop by utilizing the pressure difference.

2. The air conditioning system according to claim 1, characterized in that: The liquid storage container (107) further comprises a pressure regulating port (C), and the air conditioning system further comprises: A pressure relief branch (3) is provided with a balancing valve (111) having an on state and an off state, and a first end of the pressure relief branch (3) is in communication with the pressure regulating port (C); Wherein, when the balancing valve (111) is in an on state, the pressure in the liquid storage container (107) is released through the pressure relief branch (3).

3. The air conditioning system according to claim 1, characterized in that: The second end of the drain branch (2) is configured to be in communication with the low-pressure side pipeline in the cooling mode, and the drain valve (109) is configured to be in an on state in the cooling mode.

4. The air conditioning system according to claim 1, characterized in that: The liquid inlet valve (108) is in an on state in the defrosting mode, the liquid discharge valve (109) is in an on state in the initial stage of switching to the heating mode after the defrosting is completed, and the second end of the liquid discharge branch (2) is configured to be connected to the high-pressure side pipeline in the heating mode.

5. The air conditioning system according to claim 1, characterized in that: The liquid storage container (107) further comprises a pressure regulating port (C), and the air conditioning system further comprises: A pressurizing branch (4) is provided with a pressurizing valve (110) having an on state and an off state, and a first end of the pressurizing branch (4) is connected to the pressure regulating port (C); When the pressurizing valve (110) is in an on state, the high-pressure side pipeline pressurizes the liquid storage container (107).

6. The air conditioning system according to claim 1, characterized in that: It also includes an auxiliary liquid discharge branch (5) on which is provided an auxiliary liquid discharge valve (113) having an on state and an off state, wherein a first end of the auxiliary liquid discharge branch (5) is in communication with the liquid outlet (B), and a second end of the auxiliary liquid discharge branch (5) is in communication with the low-pressure side pipeline.

7. The air conditioning system according to claim 1, characterized in that: The liquid storage container (107) further comprises a discharge branch (6), wherein a first end of the discharge branch (6) is in communication with the liquid inlet (A), and a second end of the discharge branch (6) is in communication with the low-pressure side pipeline. The discharge branch (6) is provided with a discharge valve (112) having an on state and an off state. The discharge valve (112) is configured to be in an on state when the pressure in the liquid storage container (107) is higher than a preset safety threshold.

8. The air conditioning system according to claim 2, characterized in that: The liquid inlet (A) and the pressure regulating port (C) are arranged in the upper area of ​​the liquid storage container (107), and the liquid outlet (B) is arranged in the lower area of ​​the liquid storage container (107).

9. The air conditioning system according to claim 1, characterized in that: The refrigerant circulation loop further comprises a four-way reversing valve (103) and a gas-liquid separator (109), wherein the four-way reversing valve (103) is used for reversing when switching between a cooling mode and a heating mode, and the gas-liquid separator (109) is arranged on a pipeline between the four-way reversing valve (103) and an air intake port of the compressor (101); The air conditioning system further comprises a pressure relief branch (3) and a pressure increase branch (4), wherein the first ends of the pressure relief branch (3) and the pressure increase branch (4) are respectively connected to the pressure regulating port (C) of the liquid storage container (107), the second end of the pressure relief branch (3) is connected to the low-pressure side pipeline, and the second end of the pressure increase branch (4) is connected to the high-pressure side pipeline; The second end of the liquid discharge branch (2) is connected to the pipeline between the four-way reversing valve (103) and the evaporator, the second end of the pressurizing branch (4) is connected to the pipeline between the exhaust port of the compressor (101) and the four-way reversing valve (103), and the second end of the pressure relief branch (3) is connected between the inlet of the gas-liquid separator (109) and the four-way reversing valve (103).

10. The air conditioning system according to any one of claims 1 to 9, characterized in that: The liquid storage container (107) is built into the outdoor unit assembly (10).

11. A control method for an air conditioning system according to any one of claims 1 to 10, characterized in that: include: Liquid collecting step: placing the liquid inlet valve (108) in an on state and making the pressure at the first end of the liquid inlet branch (1) lower than the pressure at the second end, so that the refrigerant in the refrigerant circulation loop is stored in the liquid storage container (107); Discharge step: When the refrigerant in the liquid storage container (107) needs to be discharged to the refrigerant circulation circuit, the discharge valve (109) is turned on and the pressure at the first end of the discharge branch (2) is greater than the pressure at the second end.

12. The control method according to claim 11, characterized in that: The air conditioning system further comprises a pressure relief branch (3) and a pressurization branch (4), the pressure relief branch (3) being provided with a balancing valve (111), the pressurization branch (4) being provided with a pressurization valve (110), and the first ends of the pressure relief branch (3) and the pressurization branch (4) being respectively connected to the pressure regulating port (C) of the liquid storage container (107); and the control method further comprises: In the liquid collecting step, the balancing valve (111) is placed in an on state to reduce the pressure in the liquid storage container (107); In the liquid discharge step, the pressurizing valve (110) is turned on to increase the pressure in the liquid storage container (107).

13. The control method according to claim 12, characterized in that: In the refrigerant adjustment function in the cooling mode and the heating mode, the liquid collection step includes: The liquid inlet valve (108) is placed in an on state, and when the pressure difference across the liquid inlet valve (108) is less than a preset threshold, the balancing valve (111) is placed in an on state, and the liquid discharge valve (109) and the pressurizing valve (110) are both placed in an off state.

14. The control method according to claim 12, characterized in that: The second end of the liquid discharge branch (2) is configured to communicate with the low-pressure side pipeline in the cooling mode; In the refrigerant adjustment function in the refrigeration mode, the liquid discharge step includes: making the liquid discharge valve (109) in an on state, and the liquid inlet valve (108) and the balancing valve (111) both in an off state.

15. The control method according to claim 14, characterized in that: In the refrigerant adjustment function under the refrigeration mode, the liquid discharge step also includes: when the internal pressure of the liquid storage container (107) drops to the same level as the low-pressure side pipeline, the pressurizing valve (110) is placed in an on state.

16. The control method according to claim 12, characterized in that: The second end of the drainage branch (2) is configured to communicate with the high-pressure side pipeline in the heating mode; In the refrigerant adjustment function under the heating mode, the drainage step includes: placing the pressurizing valve (110) in an on state so that the pressure inside the liquid storage container (107) increases to the pressure at the second end of the pressurizing branch (4), and placing the drainage valve (109) in an on state.

17. The control method according to any one of claims 12 to 16, characterized in that: The second end of the drainage branch (2) is configured to communicate with the high-pressure side pipeline in the heating mode, and in the refrigerant transfer function, During the defrosting process, the liquid collecting step comprises: placing the liquid inlet valve (108) in an on state, and placing the liquid discharge valve (109), the balancing valve (111) and the pressurizing valve (110) in an off state; and / or In the initial stage of switching to the heating mode after defrosting, the pressurizing valve (110) is placed in an on state, so that the pressure inside the liquid storage container (107) is increased to the pressure at the second end of the pressurizing branch (4), and the drain valve (109) is placed in an on state.

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